﻿using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace MedicalSoft.Application.HIS.Util.CryptoUtil
{
    class SM4
    {
        public const int SM4_ENCRYPT = 1;
        public const int SM4_DECRYPT = 0;

        private long GET_ULONG_BE(byte[] b, int i)
        {
            long n = (long)(b[i] & 0xff) << 24 | (long)((b[i + 1] & 0xff) << 16) | (long)((b[i + 2] & 0xff) << 8) | b[i + 3] & 0xff & 0xffffffffL;
            return n;
        }

        private void PUT_ULONG_BE(long n, byte[] b, int i)
        {
            b[i] = (byte)(int)(0xFF & n >> 24);
            b[i + 1] = (byte)(int)(0xFF & n >> 16);
            b[i + 2] = (byte)(int)(0xFF & n >> 8);
            b[i + 3] = (byte)(int)(0xFF & n);
        }

        private long SHL(long x, int n)
        {
            return (x & 0xFFFFFFFF) << n;
        }

        private long ROTL(long x, int n)
        {
            return SHL(x, n) | x >> 32 - n;
        }

        private void SWAP(long[] sk, int i)
        {
            long t = sk[i];
            sk[i] = sk[31 - i];
            sk[31 - i] = t;
        }

        public byte[] SboxTable = new byte[] {  0xd6,  0x90,  0xe9,  0xfe,
             0xcc,  0xe1, 0x3d,  0xb7, 0x16,  0xb6,
            0x14,  0xc2, 0x28,  0xfb, 0x2c, 0x05, 0x2b, 0x67,
             0x9a, 0x76, 0x2a,  0xbe, 0x04,  0xc3,
             0xaa, 0x44, 0x13, 0x26, 0x49,  0x86, 0x06,
             0x99,  0x9c, 0x42, 0x50,  0xf4,  0x91,
             0xef,  0x98, 0x7a, 0x33, 0x54, 0x0b, 0x43,
             0xed,  0xcf,  0xac, 0x62,  0xe4,
             0xb3, 0x1c,  0xa9,  0xc9, 0x08,  0xe8,
             0x95,  0x80,  0xdf,  0x94,  0xfa,
            0x75,  0x8f, 0x3f,  0xa6, 0x47, 0x07,  0xa7,
             0xfc,  0xf3, 0x73, 0x17,  0xba,  0x83,
            0x59, 0x3c, 0x19,  0xe6,  0x85, 0x4f,  0xa8,
            0x68, 0x6b,  0x81,  0xb2, 0x71, 0x64,  0xda,
             0x8b,  0xf8,  0xeb, 0x0f, 0x4b, 0x70, 0x56,
             0x9d, 0x35, 0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58,  0xd1,
             0xa2, 0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78,  0x87,
             0xd4, 0x00, 0x46, 0x57,  0x9f,  0xd3, 0x27,
            0x52, 0x4c, 0x36, 0x02,  0xe7,  0xa0,  0xc4,
             0xc8,  0x9e,  0xea,  0xbf,  0x8a,
             0xd2, 0x40,  0xc7, 0x38,  0xb5,  0xa3,
             0xf7,  0xf2,  0xce,  0xf9, 0x61, 0x15,
             0xa1,  0xe0,  0xae, 0x5d,  0xa4,
             0x9b, 0x34, 0x1a, 0x55,  0xad,  0x93, 0x32,
            0x30,  0xf5,  0x8c,  0xb1,  0xe3, 0x1d,
             0xf6,  0xe2, 0x2e,  0x82, 0x66,  0xca,
            0x60,  0xc0, 0x29, 0x23,  0xab, 0x0d, 0x53, 0x4e, 0x6f,
             0xd5,  0xdb, 0x37, 0x45,  0xde,  0xfd,
             0x8e, 0x2f, 0x03,  0xff, 0x6a, 0x72, 0x6d, 0x6c, 0x5b,
            0x51,  0x8d, 0x1b,  0xaf,  0x92,  0xbb,
             0xdd,  0xbc, 0x7f, 0x11,  0xd9, 0x5c, 0x41,
            0x1f, 0x10, 0x5a,  0xd8, 0x0a,  0xc1, 0x31,
             0x88,  0xa5,  0xcd, 0x7b,  0xbd, 0x2d,
            0x74,  0xd0, 0x12,  0xb8,  0xe5,  0xb4,
             0xb0,  0x89, 0x69,  0x97, 0x4a, 0x0c,
             0x96, 0x77, 0x7e, 0x65,  0xb9,  0xf1, 0x09,
             0xc5, 0x6e,  0xc6,  0x84, 0x18,  0xf0,
            0x7d,  0xec, 0x3a,  0xdc, 0x4d, 0x20, 0x79,
             0xee, 0x5f, 0x3e,  0xd7,  0xcb, 0x39, 0x48 };

        public uint[] FK = { 0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc };

        public uint[] CK = { 0x00070e15,0x1c232a31,0x383f464d,0x545b6269,
                                        0x70777e85,0x8c939aa1,0xa8afb6bd,0xc4cbd2d9,
                                        0xe0e7eef5,0xfc030a11,0x181f262d,0x343b4249,
                                        0x50575e65,0x6c737a81,0x888f969d,0xa4abb2b9,
                                        0xc0c7ced5,0xdce3eaf1,0xf8ff060d,0x141b2229,
                                        0x30373e45,0x4c535a61,0x686f767d,0x848b9299,
                                        0xa0a7aeb5,0xbcc3cad1,0xd8dfe6ed,0xf4fb0209,
                                        0x10171e25,0x2c333a41,0x484f565d,0x646b7279 };

        private byte sm4Sbox(byte inch)
        {
            int i = inch & 0xFF;
            byte retVal = SboxTable[i];
            return retVal;
        }

        private long sm4Lt(long ka)
        {
            long bb = 0L;
            long c = 0L;
            byte[] a = new byte[4];
            byte[] b = new byte[4];
            PUT_ULONG_BE(ka, a, 0);
            b[0] = sm4Sbox(a[0]);
            b[1] = sm4Sbox(a[1]);
            b[2] = sm4Sbox(a[2]);
            b[3] = sm4Sbox(a[3]);
            bb = GET_ULONG_BE(b, 0);
            c = bb ^ ROTL(bb, 2) ^ ROTL(bb, 10) ^ ROTL(bb, 18) ^ ROTL(bb, 24);
            return c;
        }

        private long sm4F(long x0, long x1, long x2, long x3, long rk)
        {
            return x0 ^ sm4Lt(x1 ^ x2 ^ x3 ^ rk);
        }

        private long sm4CalciRK(long ka)
        {
            long bb = 0L;
            long rk = 0L;
            byte[] a = new byte[4];
            byte[] b = new byte[4];
            PUT_ULONG_BE(ka, a, 0);
            b[0] = sm4Sbox(a[0]);
            b[1] = sm4Sbox(a[1]);
            b[2] = sm4Sbox(a[2]);
            b[3] = sm4Sbox(a[3]);
            bb = GET_ULONG_BE(b, 0);
            rk = bb ^ ROTL(bb, 13) ^ ROTL(bb, 23);
            return rk;
        }

        private void sm4_setkey(long[] SK, byte[] key)
        {
            long[] MK = new long[4];
            long[] k = new long[36];
            int i = 0;
            MK[0] = GET_ULONG_BE(key, 0);
            MK[1] = GET_ULONG_BE(key, 4);
            MK[2] = GET_ULONG_BE(key, 8);
            MK[3] = GET_ULONG_BE(key, 12);
            k[0] = MK[0] ^ FK[0];
            k[1] = MK[1] ^ FK[1];
            k[2] = MK[2] ^ FK[2];
            k[3] = MK[3] ^ FK[3];
            for (; i < 32; i++)
            {
                k[i + 4] = k[i] ^ sm4CalciRK(k[i + 1] ^ k[i + 2] ^ k[i + 3] ^ CK[i]);
                SK[i] = k[i + 4];
            }
        }

        private void sm4_one_round(long[] sk, byte[] input, byte[] output)
        {
            int i = 0;
            long[] ulbuf = new long[36];
            ulbuf[0] = GET_ULONG_BE(input, 0);
            ulbuf[1] = GET_ULONG_BE(input, 4);
            ulbuf[2] = GET_ULONG_BE(input, 8);
            ulbuf[3] = GET_ULONG_BE(input, 12);
            while (i < 32)
            {
                ulbuf[i + 4] = sm4F(ulbuf[i], ulbuf[i + 1], ulbuf[i + 2], ulbuf[i + 3], sk[i]);
                i++;
            }
            PUT_ULONG_BE(ulbuf[35], output, 0);
            PUT_ULONG_BE(ulbuf[34], output, 4);
            PUT_ULONG_BE(ulbuf[33], output, 8);
            PUT_ULONG_BE(ulbuf[32], output, 12);
        }

        private byte[] padding(byte[] input, int mode)
        {
            if (input == null)
            {
                return null;
            }

            byte[] ret = null;
            if (mode == SM4_ENCRYPT)
            {
                int p = 16 - input.Length % 16;
                ret = new byte[input.Length + p];
                Array.Copy(input, 0, ret, 0, input.Length);
                for (int i = 0; i < p; i++)
                {
                    ret[input.Length + i] = (byte)p;
                }
            }
            else
            {
                int p = input[input.Length - 1];
                ret = new byte[input.Length - p];
                Array.Copy(input, 0, ret, 0, input.Length - p);
            }
            return ret;
        }

        public void sm4_setkey_enc(SM4_Context ctx, byte[] key)
        {
            ctx.mode = SM4_ENCRYPT;
            sm4_setkey(ctx.sk, key);
        }

        public void sm4_setkey_dec(SM4_Context ctx, byte[] key)
        {
            int i = 0;
            ctx.mode = SM4_DECRYPT;
            sm4_setkey(ctx.sk, key);
            for (i = 0; i < 16; i++)
            {
                SWAP(ctx.sk, i);
            }
        }

        public byte[] sm4_crypt_ecb(SM4_Context ctx, byte[] input)
        {
            if (ctx.isPadding && ctx.mode == SM4_ENCRYPT)
            {
                input = padding(input, SM4_ENCRYPT);
            }

            int length = input.Length;
            byte[] bins = new byte[length];
            Array.Copy(input, 0, bins, 0, length);
            byte[] bous = new byte[length];
            for (int i = 0; length > 0; length -= 16, i++)
            {
                byte[] inBytes = new byte[16];
                byte[] outBytes = new byte[16];
                Array.Copy(bins, i * 16, inBytes, 0, length > 16 ? 16 : length);
                sm4_one_round(ctx.sk, inBytes, outBytes);
                Array.Copy(outBytes, 0, bous, i * 16, length > 16 ? 16 : length);
            }

            if (ctx.isPadding && ctx.mode == SM4_DECRYPT)
            {
                bous = padding(bous, SM4_DECRYPT);
            }
            return bous;
        }

        public byte[] sm4_crypt_cbc(SM4_Context ctx, byte[] iv, byte[] input)
        {
            if (ctx.isPadding && ctx.mode == SM4_ENCRYPT)
            {
                input = padding(input, SM4_ENCRYPT);
            }

            int i = 0;
            int length = input.Length;
            byte[] bins = new byte[length];
            Array.Copy(input, 0, bins, 0, length);
            byte[] bous = null;
            List<byte> bousList = new List<byte>();
            if (ctx.mode == SM4_ENCRYPT)
            {
                for (int j = 0; length > 0; length -= 16, j++)
                {
                    byte[] inBytes = new byte[16];
                    byte[] outBytes = new byte[16];
                    byte[] out1 = new byte[16];

                    Array.Copy(bins, i * 16, inBytes, 0, length > 16 ? 16 : length);
                    for (i = 0; i < 16; i++)
                    {
                        outBytes[i] = (byte)(inBytes[i] ^ iv[i]);
                    }
                    sm4_one_round(ctx.sk, outBytes, out1);
                    Array.Copy(out1, 0, iv, 0, 16);
                    for (int k = 0; k < 16; k++)
                    {
                        bousList.Add(out1[k]);
                    }
                }
            }
            else
            {
                byte[] temp = new byte[16];
                for (int j = 0; length > 0; length -= 16, j++)
                {
                    byte[] inBytes = new byte[16];
                    byte[] outBytes = new byte[16];
                    byte[] out1 = new byte[16];

                    Array.Copy(bins, i * 16, inBytes, 0, length > 16 ? 16 : length);
                    Array.Copy(inBytes, 0, temp, 0, 16);
                    sm4_one_round(ctx.sk, inBytes, outBytes);
                    for (i = 0; i < 16; i++)
                    {
                        out1[i] = (byte)(outBytes[i] ^ iv[i]);
                    }
                    Array.Copy(temp, 0, iv, 0, 16);
                    for (int k = 0; k < 16; k++)
                    {
                        bousList.Add(out1[k]);
                    }
                }

            }

            if (ctx.isPadding && ctx.mode == SM4_DECRYPT)
            {
                bous = padding(bousList.ToArray(), SM4_DECRYPT);
                return bous;
            }
            else
            {
                return bousList.ToArray();
            }
        }
    }
}